RESUMEN
This study investigated the acute toxicity in Clarias gariepinus to insecticides currently used in Benin cotton fields, including Thalis 112 EC (Emamectin benzoate 48 g L-1, Acetamiprid 64 g L-1), Vizir C 92 EC (Cypermethrin 72 g L-1, Abamectin 20 g L-1), Pyrinex Quick 212 EC (Deltamethrin 12 g L-1, Chlorpyrifos 200 g L-1) and Pyro FTE 472 EC (Cypermethrin 72 g L-1, Chlorpyrifos 400 g L-1) with emphasis on liver histopathological effects. A set of 180 juveniles of C. gariepinus (5.21 ± 3.22 g) was exposed for 96 h to increasing concentrations of each pesticide. The values of 96-hLC50 were 4.778, 0.002, 0.004, and 0.012 µL L-1 for Thalis, Vizir, Pyrinex, and Pyro, respectively, indicating that Vizir, Pyrinex, and Pyro were very highly toxic to C. gariepinus juveniles. During the experiments, the morphological and behavioral responses (discoloration, hyperactivity, lethargy, etc.) were observed in exposed fish, hypothesizing the neurotoxicity of these pesticides. Histopathological alterations observed in liver of contaminated fish were regressive changes, such as necrosis, vacuolation, bleeding, nuclear degeneration, hepatocytes degeneration, sinusoids dilatation, etc. Vizir induced the highest histological alteration indices while the lowest were induced by Thalis, confirming the highest toxicity of Vizir. These results indicate that acute concentrations of these insecticidal molecules have destructive effects on the liver of C. gariepinus.
Asunto(s)
Bagres , Cloropirifos , Insecticidas , Plaguicidas , Contaminantes Químicos del Agua , Animales , Insecticidas/toxicidad , Bagres/fisiología , Plaguicidas/farmacología , Hígado , Contaminantes Químicos del Agua/toxicidadRESUMEN
Aquatic organisms are exposed to chemical pesticides including glyphosate (Sharp 480 SL) and atrazine (Atraforce), two phytocidal molecules used for agriculture purposes in Benin. In this study, we assessed the acute toxicity of these two herbicides with emphasis on their histopathological effects on the liver of catfish Clarias gariepinus. One hundred and eighty juveniles of C. gariepinus (mean length 7.26 ± 0.59 cm and mean weight 5.21 ± 3.22 g) were exposed over 96 h to increasing concentrations of each phytocide. The values of 96 h-LC50 were 6.175 × 103 and 3.165 ppm, respectively for Sharp 480 SL and Atraforce. This indicates that Sharp 480 SL was nontoxic, while Atraforce displayed a moderate toxicity to C. gariepinus juveniles. During the tests, the behavioral responses (hyperexcitation, lethargy, loss of balance, discoloration of skin, etc.) that usually precede death were observed in exposed fishes, confirming the neurotoxicity of these phytocides. Histological alterations observed in liver of contaminated fishes were regressive changes, such as necrosis, hepatocyte vacuolation, nuclear degeneration, hepatocytes degeneration, sinusoids dilatation, etc. These results indicate that exposure to these herbicides had destructive effects on the liver of C. gariepinus.
Asunto(s)
Atrazina , Bagres , Herbicidas , Contaminantes Químicos del Agua , Animales , Atrazina/farmacología , Hígado , Herbicidas/farmacología , Contaminantes Químicos del Agua/toxicidad , GlifosatoRESUMEN
An in-situ study combined with an integrated biomarker response was used to evaluate the impact of agricultural effluents in the physiological responses of Nile tilapia reared in cages and enclosures of water reservoirs in North Benin. Fish were distributed in fish farming systems at two sites: Songhai located outside the cotton basin and Batran located in the most productive commune. They were sampled for blood and organs before (BST), during (DST) and after (AST) pesticide treatment. Pesticide residues were analysed in water, sediments and fish muscles. Several biomarkers were investigated related to the immune (peroxidase, lysozyme and complement activities, superoxide anion production) and reproductive (sex steroids and vitellogenin levels) responses as well as neurotoxicity (cholinesterase activity) and tissue alterations. Biomarkers were assessed and analysed via the integrated biomarker response (IBR). The results showed that Batran water reservoir was a more harmful ecosystem for fish than Songhai one, especially by depressing some immune and reproductive functions in relation to a higher-level of pesticide contamination. They also demonstrated that the contact of fish to sediments in enclosures aggravated the pesticide burden on fish. Therefore, using males as bioindicators would improve the sensitivity of the used biomarkers since males seemed more affected than females especially due to pesticide estrogenic induction impacting their reproductive system.
Asunto(s)
Cíclidos , Residuos de Plaguicidas , Plaguicidas , Contaminantes Químicos del Agua , Animales , Biomarcadores/análisis , Ecosistema , Monitoreo del Ambiente/métodos , Femenino , Masculino , Residuos de Plaguicidas/análisis , Plaguicidas/análisis , Agua/análisis , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/toxicidadRESUMEN
This study was designed to evaluate the acute toxicity of acetamiprid (neonicotinoid) and lambda-cyhalothrin (pyrethroid), individually and mixtures (Act-LCh mixture and Acer 35 EC®, 15 g/L of acetamiprid and 20 g/L of lambda-cyhalothrin) in African catfish juveniles (3.35 ± 0.75 g). The tests were conducted in the laboratory under semi-static conditions according to OECD Guideline 203. Mixture toxicity effects as a function of lethal concentrations were assessed using the additive index (AI) method. Acetamiprid with 96 h-LC50 = 265.7 ppm can be considered to be nontoxic for this species. However, lambda-cyhalothrin was highly toxic to C. gariepinus with 96 h-LC50 = 0.00083 ppm. Acer 35 EC® was less toxic (96 h-LC50 = 0.21 ppm) than the Act-LCh mixture (96 h-LC50 = 0.043 ppm). Marked changes indicating nervous system damage were also recorded. An antagonistic effect was shown for lethal concentrations leading to 5 to 15% mortality in 96 hours (96 h-LC5-15) while an additive effect was obtained for the 96 h-LC20-50. The results indicate that ecological risk assessment of these molecules in aquatic environments should consider their contamination levels. Moreover, particular attention to behavior changes related to their neurotoxicity is recommended for additional monitoring of the negative effects of these insecticides.
Asunto(s)
Bagres , Neonicotinoides/toxicidad , Nitrilos/toxicidad , Piretrinas/toxicidad , Contaminantes Químicos del Agua/toxicidad , Animales , Conducta Animal/efectos de los fármacos , Ecotoxicología/métodos , Insecticidas/toxicidad , Dosificación Letal Mediana , Mortalidad , Pruebas de Toxicidad AgudaRESUMEN
This study aimed to compare the toxicity for fish of two active ingredients (lambda-cyhalothrin-20 g L-1, a pyrethroid, and acetamiprid-15 g L-1, a neonicotinoid) which are components of a commercial insecticide (Acer 35 EC) used in cotton crop in many West African countries. The juveniles of Oreochromis niloticus (4.01 ± 0.34 g, mean body weight) were exposed for 96 h to increasing concentrations of active ingredients (lambda-cyhalothrin and acetamiprid) or a mixture similar to Acer 35 EC (composed by 20 g of chemical compound lambda-cyhalothrin and 15 g of acetamiprid dissolved in 1 L of acetone). The experiments were carried out under controlled conditions in aquaria according to OECD Guidelines. During the experiments, the behavioral responses (loss of balance, color change, hyperactivity, etc.) that usually precede death were observed in exposed fish. Mortalities were recorded in each aquarium and the LC50-96h of each chemical was determined. The LC50-96h obtained were respectively 0.1268, 0.0029, 182.9 and 0.5685 ppm for Acer 35 EC, lambda-cyhalothrin, acetamiprid and mixture. All insecticides used in this study had profound impact on Nile tilapia behavior which may confirm the neurotoxicity of each single active compound as well as of their mixture.
Asunto(s)
Cíclidos , Neonicotinoides/toxicidad , Nitrilos/toxicidad , Piretrinas/toxicidad , Animales , Conducta Animal/efectos de los fármacos , Cíclidos/fisiología , Sinergismo Farmacológico , Insecticidas/toxicidad , Dosificación Letal Mediana , Mortalidad , Pruebas de Toxicidad Aguda , Contaminantes Químicos del Agua/toxicidadRESUMEN
To determine the impact of agricultural pesticides used in cotton cultivation on the health status of fish living in a Beninese cotton basin, we compared the reproductive and hepatic systems of fish sampled from rivers located in both contaminated and pristine conditions. Different types of biomarkers, including biometric indices (a condition factor K, a gonadosomatic index GSI, and a hepatosomatic index HSI), plasma levels of sex steroids (11-ketotestosterone 11-KT, testosterone T and estradiol-17ß E2) and the histopathology of the gonads and liver, were investigated for two different trophic levels of the following two fish species: the Guinean tilapia Tilapia guineensis and the African catfish Clarias gariepinus. The fish were captured during both the rainy season (when there is heavy use of pesticides on cotton fields) and the dry season from one site, in Pendjari River (reference site), which is located outside the cotton-producing basin, and from three other sites on the Alibori River within the cotton-producing basin. Comparing fish that were sampled from contaminated (high levels of endosulfan, heptachlor and DDT and metabolites) and reference sites, the results clearly indicated that agricultural pesticides significantly decreased K and GSI while they increased HSI, regardless of the season, species and sex of the fish. These pesticides also induced a decrease in the plasma levels of 11-KT and T and increased those of E2. The histopathology of the testes revealed, in both species, a high rate of testicular oocytes, up to 50% in the African catfish, downstream of the Alibori River, which indicated estrogenic effects from the pesticides. The disruption of male spermatogenesis primarily included necrosis, fibrosis and the presence of foam cells in the lobular lumen. The histopathology of the ovaries revealed high levels of pre-ovulatory follicular atresia, impaired oogenesis, a decrease in the oocyte vitellogenic diameter and other lesions, such as fibrosis, vacuolation and melano-macrophagic centers. The histopathology of the liver revealed the presence of necrosis, hypertrophic hepatocytes, foci of vacuolation, glycogen depletion and hemosiderin. An assessment of the general health of the fish indicated that all of the sampled fish from the polluted sites were in poorer health compared with those from the reference site but that the African catfish appeared much more affected than the Guinean tilapia, regardless of the sex and season. In conclusion, the overall results indicated that agricultural pesticides significantly impair the endocrine regulation of fish living in the Beninese cotton basin and that this would most likely be one of the causes of the severe damage observed in the liver and gonads and the reduced health condition.
Asunto(s)
Monitoreo del Ambiente , Plaguicidas/toxicidad , Contaminantes Químicos del Agua/toxicidad , Agricultura , Animales , Benin , Estradiol/metabolismo , Femenino , Peces/metabolismo , Gónadas/efectos de los fármacos , Gónadas/metabolismo , Estado de Salud , Hígado/efectos de los fármacos , Hígado/metabolismo , Masculino , Ovario/efectos de los fármacos , Plaguicidas/metabolismo , Reproducción/efectos de los fármacos , Espermatogénesis/efectos de los fármacos , Testículo/efectos de los fármacos , Testosterona/análogos & derivados , Testosterona/metabolismo , Vitelogeninas/metabolismo , Contaminantes Químicos del Agua/metabolismoRESUMEN
We exposed African catfish Clarias gariepinus from embryo-larvae stage to adult stage (13 months old, BW) to chronic doses of Tihan 175 O-TEQ and endosulfan (Thionex) and assessed the impact of this exposure on endocrine regulation, liver status and offspring fitness. Endosulfan exposure caused a significant increase in plasma estradiol-17ß (E2) and decreased plasma testosterone (T) but not 11 ketotestosterone (11-KT). Tihan decreased significantly plasma E2 and 11-KT, but not T. Endosulfan doses altered gonad histology and induced high proportions (1830% of males) of ovotestis in males and follicular atretic oocytes in females, indicating occurrence of feminization in fish. Tihan also altered gonad histology but only one case of ovotestis was observed at the highest dose. Presence of foam cells in lobular lumen, fibrosis, necrosis, and immature cells released in lobular lumen were found in male gonads and melano-macrophage centers (MMCs), necrosis, fibrosis and vacuolation were observed in female gonads. Fish livers also suffered injuries such as MMCs, necrosis, fibrosis, vacuolation, dilatation of sinusoids, and nuclear pleomorphism. Chronic Tihan and Thionex exposures decreased fertilization rate, hatching rate, ova and larval weight, as well as larval resistance to osmotic choc. They also delayed hatching and increased abnormalities in the F1 generation, all these indicators suggesting transgenerational effects of these compounds.